Great value LED battery operated butterfly fairy lights. This set features 50 bright warm white LED butterfly cap bulbs on a 5 metre green cable, waterproof battery box, twinkle/steady setting and a timer function. Ideal for outdoor trees, bushes, hedges, decking and for all events: including bbq's, weddings, Christmas, parties and festivals. We almost forgot...of course you can use them indoor as well! The plastic battery pack is both robust and waterproof ensuring the batteries, function switch and timer survive all that the British weather can throw at it. When the lights are set to the timer function via a switch on the battery box they will stay lit for 6 hours. After being lit for 6 hours they will turn off for the next 18 hours and then come on again. This is brilliant for two reasons, firstly it saves you having to remember to switch your beautiful lights on/off every night and secondly it conserves the battery life. The butterfly caps will need to be inserted onto each bulb. The battery lights take 3 x 'AA' type batteries (not provided). So to sum up... you can have the ultra bright led lights you've always wanted but with no need for an outdoor socket and as a bonus you can have them twinkling and set on a timer function.